Drafting

alarm

#1

Can I benefit from the semis that pass me? Since I prefer to stay in the right lane is there any “pull” I get from trucks passing me??


#2

Yes, but only if you are following at a very unsafe distance. It’s not a good idea!


#3

Not safely. You have to get perilously close to the back of a semi to get any meaningful draft. I recall them testing this out on Mythbusters a while back.


#4

Yup…I think the boys decided you had to be ridiculously close to benefit. You couldn’t pay me enough to follow a semi that closely!

Edit: I looked it up, and I exaggerated. They tested down to 2 feet and said that the greatest improvement they saw was 10 feet, but that 2 feet is so difficult to maintain it may not have been accurate.


#5

The Mythbusters tested drafting at various speeds; sitting at 100 feet, 50 feet, etc. down to 10 feet. They showed definite improvements in mpg the closer you sat. The catch is the safety issue. At highway speeds, keep back a minimum distance of 150 ft. Sticking any closer is insane.


#6

There is a benefit to drafting, but it isn’t worth it. Truck drivers are allowed to use recapped tires everywhere except the steering tires. This means you could find a large piece of truck tire tread flung at your car at high speed. If it penetrates your windshield, it could decapitate you. At best, it could really mess up your car.

Keep in mind that you are really following a towed trailer. If the electrical connection between the truck and the trailer isn’t sound (which happens more often than you think), the brake lights on the trailer might not come on. If they do come on, they might not be bright enough to see.

If you are serious about drafting, get a CB radio so you get permission from the truck driver. Make sure he did a thorough pre-trip inspection on the truck tires and the trailer tires and that he is comfortable with you putting your and his life in danger. Then if he gives you permission and you have your affairs in order (your will, etc.), go for it. Of course, he won’t know if his axle is about to break or if his fifth wheel is about malfunction, causing his trailer to fall off the back of his truck. So even if you have the truck driver’s permission, you should be prepared to die. Good luck with your drafting.


#7

Next time you’re behind a late model semi trailer notice the large rectangular tubing guard on the back behind the rear wheels. It’s to, hopefully, prevent cars from sliding underneath and decapitating the car’s occupants.

Drafting is beneficial but the danger outweighs the benefits and it’s amazing how quick 90k pounds of loaded semi can stop when the air brakes are locked up.

Leave this stuff to the race car guys.


#8

I don’t think Laura is asking about actually drafting a semi. It sounds like she just wants to know if she is currently reaping any benefit from the trucks passing her.

Laura: No. While there may be a slight tug forward from the faster moving vehicle, this will be more than offset by the area of turbulent air those babies leave in their wake.